Hypothesis testing and parameter estimation based onM-statistics ink samples with unequal variances

Summary Ink samples with unequal variances,M-tests for homogeneity ofk location parameters are proposed. The asymptoticχ ²-distributions of the test statistics and the robustness of the tests are investigated. NextM-estimators (ME’s) of parameters are discussed. Furthermore positive-part shrinkage versions (PSME’s) of theM-estimators for the location parameters are considered along with modified James-Stein estimation rule. In asymptotic distributional risks based on a special feasible loss, it is shown that the PSME’s dominate the ME’s, and preliminary test and shrinkageM-versions fork≧4.     

Can Warren Buffett forecast equity market corrections?

Warren Buffett suggested that the ratio of the market value of all publicly traded stocks to the Gross National Product could identify potential overvaluations and undervaluations in the US equity market when this ratio deviates above 120% or below 80%. We investigate whether this ratio is a statistically significant predictor of equity market corrections and rallies. We find that Buffett's decision rule does not deliver satisfactory forecasts. However, when we adopt a time-varying decision rule, the ratio becomes a statistically significant predictor of equity market corrections. The two time-varying decision rules are: (i) predict an equity market correction when the ratio exceeds a 95% one-tail confidence interval based on a normal distribution, and (ii) predict an equity market correction when the ratio exceeds a threshold computed using Cantelli's inequality. These new decision rules are robust to changes in the two key parameters: the confidence level and the forecasting horizon. This paper also shows that the MV/GNP ratio performs relatively well against the four most popular equity market correction models, but the ratio is not a particularly useful predictor of equity market rallies.     

“好”的不确定性、“坏”的不确定性与股票市场定价——基于中国股市高频数据分析

不确定性并不是都是“坏”的,“好”的不确定性也同样存在。本文采用Barndorff-Nielsen et al.(2010)提出的已实现半方差作为股票市场“好”的不确定性和“坏”的不确定性的代理指标,并在此基础上构建了相对符号变差(RSV),分析RSV对中国股市定价的影响。基于2007-2017年中国A股5分钟高频数据的实证研究发现:(1)与理论解释相一致,RSV与股票收益之间呈现负相关关系。无论是基于单变量分组、双变量分组还是公司层面的截面回归,这种影响在经济上和统计上都显著。(2)RSV是独立于已实现偏度的一个重要定价因子,且RSV对股票的定价能力强于已实现偏度的定价能力。(3)RSV对中国股市的影响是状态依存的,相对于经济景气程度高的状态,在经济景气程度低的状态下RSV定价影响更大。(4)基于RSV构建的投资组合的表现明显优于市场超额收益率组合、SMB组合和HML组合的表现。     

The effect of relative performance feedback on individual performance in team settings under group-based incentives*

This study reports the results of an experiment that analyses the behavioural effect of relative performance feedback (RPF) on individual performance when compensation is based on team performance. Specifically, it investigates whether RPF affects individual performance differently when the comparison focuses on other members of that individual’s team (within-group RPF) or on other teams (between-group RPF). We predict a negative effect of within-group RPF on individual performance. We also predict that between-group RPF moderates that negative effect, since it encourages individuals to focus on group goals rather than individual goals. Consistent with our predictions, results show that the negative effect of within-group RPF on individual performance is mitigated by between-group RPF. Our results can help accountants to better understand how the effects of relative performance feedback differ according to the predominant comparison target.     

Robustness and U.S. Monetary Policy Experimentation

We study how a concern for robustness modifies a policymaker's incentive to experiment. A policymaker has a prior over two submodels of inflation‐unemployment dynamics. One submodel implies an exploitable trade‐off, the other does not. Bayes' law gives the policymaker an incentive to experiment. The policymaker fears that both submodels and his prior probability distribution over them are misspecified. We compute decision rules that are robust to misspecifications of each submodel and of the prior distribution over submodels. We compare robust rules to ones that Cogley, Colacito, and Sargent (2007) computed assuming that the models and the prior distribution are correctly specified. We explain how the policymaker's desires to protect against misspecifications of the submodels, on the one hand, and misspecifications of the prior over them, on the other, have different effects on the decision rule.     

Tax incentives for inefficient executive pay and reward for luck

I study the economic consequences of tax deductibility limits on salaries for the design of incentive contracts. The analysis is based on an agency model in which the firm’s cash flow is a function of the agent’s effort and an observable random factor beyond the agent’s control. According to my analysis, limiting the tax deductibility of fixed wages has two consequences. The principal rewards the agent on the basis of the observable random factor and adjusts the amount of performance-based pay in the optimal incentive contract. The new contract can have weaker or stronger work incentives than without the tax. The theoretical findings have implications for empirical compensation research. First, the analysis shows that reward for luck can be the optimal response to recent tax law changes, whereas earlier empirical literature has attributed this phenomenon to managerial entrenchment. Second, I demonstrate that a simple regression analysis that fails to control for separable measures of luck is likely to find an increased pay for performance sensitivity as a response to the introduction of tax deductibility limits on salaries even if the pay for performance sensitivity has actually declined.     

The relative and incremental explanatory powers of dirty surplus items for debt interest rate

This study investigates the relationship between dirty surplus items on the balance sheet and the cost of debt for Japanese firms. We focus on three dirty surplus items—unrealized gains and losses on available-for-sale securities (SEC), foreign currency translation adjustment (FOC), and land revaluation surplus (LAND). While many previous studies on dirty surplus adopted the value-relevance perspective, we examine the effect of dirty surplus items on the interest rate spread of bonds from the bond market perspective. We use the [Vuong, Q. H. (1989). Likelihood ratio tests for model selection and non-nested hypotheses. Econometrica, 57, 307–333] test to evaluate the relative explanatory power of the equity ratio with and without dirty surplus items for the interest rate spread on bonds issued. We find evidence that the equity ratio with dirty surplus items is more strongly associated with the debt interest rate than that without dirty surplus items. The results suggest that the total amount of dirty surplus items have statistically significant explanatory power for the interest rate spread. However, some dirty surplus items do not have explanatory powers for the bond interest rate spread. While FOC has relative and incremental explanatory powers and SEC has only incremental explanatory power, LAND has neither relative nor incremental explanatory power for the bond interest rate spread. The results mean that FOC and SEC are useful to Japanese bond investors.     

Convex risk measures for the aggregation of multiple information sources and applications in insurance

We propose a novel class of convex risk measures, based on the concept of the Fréchet mean, designed in order to handle uncertainty which arises from multiple information sources regarding the risk factors of interest. The proposed risk measures robustly characterize the exposure of the firm, by filtering out appropriately the partial information available in individual sources into an aggregate model for the risk factors of interest. Importantly, the proposed risks can be expressed in closed analytic forms allowing for interesting qualitative interpretations as well as comparative statics and thus facilitate their use in the everyday risk management process of the insurance firms. The potential use of the proposed risk measures in insurance is illustrated by two concrete applications, capital risk allocation and premia calculation under uncertainty.     

基于个税递延政策的企业年金保障水平研究

国家明确以税收优惠的形式鼓励和引导企业和个人参加企业年金计划,并于2014年实施了个税递延政策。基于指标模型构建和数据模拟,本文对我国企业年金在个税递延政策实施前后的保障水平进行了比较,通过参数敏感性分析考察了投资收益、工资增长、退休年龄和缴费比例等因素的影响。研究发现,实施个税递延政策后企业职工的养老保障水平在较大程度上低于政策实施前,但不同性别、不同收入水平和不同缴费比例的企业职工保障水平降低的程度有所差异。收入水平和缴费比例越高的男性职工,个税递延政策实施后保障水平降低的幅度越高,但对女性职工而言,这种影响要弱一些。进一步,可以通过增加投资收益、延迟退休年龄和提升缴费比例等方法来提高企业职工的养老保障水平,这与目前正在进行的一系列改革方向也一致。